The role of higher silanes in silane-discharge particle growth

A small concentration of stable higher silanes (HS) build up in an (initially) pure-silane discharge. Here it is shown that these HS cause a major increase in particle growth rates but have no effect on film growth rates. This explains the observed increase of growth rate during the first seconds of a transient discharge, as the HS build up toward a steady-state concentration of several percent. A rapid increase in particle versus film growth rate also occurs at larger values of discharge power and pressure, and the HS also appear to cause this. Possible reasons for this extreme sensitivity of particles, but not of films, to the HS are evaluated.